This topic has come up many times and, if you do a search, you'll find past discussions.

Trying to get an accurate read on the personal wealth of criminals, who tend not to report their income, is largely futile. Even the official estimates are often all over the place.

And many of the, including the ones above, are grossly inflated. Salerno was certainly a millionaire but nowhere near $600 million. Even the more oft-cited $100 million for him is probably a stretch. And the $9 billion for Escobar is also inflated. The Rodriguez Orejuela brothers from the Cali had to fork over most of their wealth (about $2 billion). Chapo Guzman of the Sinaloa cartel is estimated to be worth about $1 billion. So it's unlikely that Escobar alone was worth so much more. The figure you usually see for Lansky is $300 million but that's certainly a stretch. I don't believe he was broke when he died but was never worth anywhere near that much.